Piezoelectric Ceramic Pressure Sensors

Piezoelectric Ceramic Pressure Sensors, also called Piezoresistive Ceramic Pressure Sensors, are devices that convert mechanical pressure changes into electrical signals by utilizing the piezoelectric effect, which refers to the generation of an electric charge in certain materials when subjected to mechanical stress; ceramic materials are commonly used as substrates for these sensors due to their high sensitivity, excellent compressive strength, and ability to function reliably over a wide temperature range, making these sensors ideal for high-precision pressure measurements in industries such as automotive, healthcare, and industrial automation.

Piezoelectric Ceramic Pressure Sensors are manufactured by combining thick-film hybrid circuit technology with ceramic substrates. The ceramic materials are selected for their durability, pressure resistance, and thermal stability, ensuring that the sensors perform reliably in harsh environments. During production, piezoelectric ceramic elements are fabricated using high-temperature sintering and laser trimming to achieve precise shapes and performance. Hybrid thick-film circuits are then applied to the ceramic substrates to create the electrical contacts and signal processing elements required for the sensor.

Piezoresistive Ceramic Pressure Sensors are widely used in various industrial and scientific applications. In the automotive industry, these sensors are used for tire pressure monitoring, fuel pressure detection, and in hydraulic systems to ensure vehicle performance and safety. In medical devices, they are essential for accurate pressure measurement in blood pressure monitors, ventilators, and other diagnostic equipment, which are crucial for patient care. Additionally, these sensors are applied in industrial processes such as monitoring pressures in pipelines, pumps, and compressors, providing real-time data to ensure safety and efficiency in high-risk environments.

Features of Piezoelectric Ceramic Pressure Sensors :

● High Sensitivity: With a typical sensitivity range of 1.5 to 4mV/V, these sensors can detect even minor changes in pressure with precision.

● Wide Pressure Range: Available in various pressure ranges from 2bar to 100bar, these sensors can cater to different measurement needs.

● Versatile Operating Voltage: They operate on a wide voltage range of 2-20V, providing flexibility for integration into various systems.

● Temperature Resilience: Designed to function effectively in a broad temperature spectrum from -40℃ to 125℃, ensuring reliable performance in extreme conditions.

● Linearity and Repeatability: The Piezoelectric Ceramic Pressure Sensors boast a typical linearity, hysteresis, and repeatability of ±0.3 %FS, indicating consistent and accurate measurements.

● Low Temperature Drift: A typical temperature drift of ±0.05%FS/°C minimizes errors due to temperature variations.

● Safe Overload Capacity: Capable of withstanding a safe overload of up to 2 times the rated full scale, safeguarding the sensor from damage during transient pressure spikes.

● Long-Term Stability: Exhibits better than ±0.5%FS/year stability under reasonable operating conditions, ensuring reliable long-term performance.

● Compact Size: Measuring 18mm in diameter and 6.35mm in length, these sensors are designed for easy integration into tight spaces.

Applications of Piezoelectric Ceramic Pressure Sensors :

Piezoelectric Ceramic Pressure Sensors find use in a multitude of applications due to their precision and resilience:

● Industrial Automation: For monitoring and controlling pressure in manufacturing processes.

● Medical Equipment: In devices that require precise measurement of blood pressure or respiratory pressure.

● Aerospace: To measure pressure in engines, fuel systems, and environmental control systems.

● Hydraulic Systems: For detecting and managing pressure in hydraulic fluids for machinery and vehicles.

● Research and Development: In laboratories for scientific experiments requiring accurate pressure data.

● Environmental Monitoring: To measure atmospheric pressure changes in weather stations and climate research.

● Automotive: In fuel injection systems and tire pressure monitoring systems for enhanced vehicle performance and safety.

Monolithic VS Piezoresistive Ceramic Pressure Sensors :

1, Working Principle:

● Piezoresistive Ceramic Pressure Sensors: Utilize the piezoelectric effect, where mechanical pressure applied to the piezoelectric material generates an electrical charge. These sensors are typically used for measuring dynamic or quasi-static stress, such as acceleration, pressure, and vibration. They are widely used in applications where the sensing of mechanical stress or energy conversion is required.

● Monolithic Ceramic Sensors: Generally refer to pressure sensors made from a single piece of ceramic material. They may operate on different sensing principles, such as changes in capacitance or resistance to detect pressure. Monolithic sensors are known for their robustness and are often used in harsh environments.

2, Structural Characteristics:

● Piezoresistive Ceramic Pressure Sensors: May consist of a multi-layer structure, with each layer containing piezoelectric materials like PZT (Lead Zirconate Titanate), along with electrodes and insulating layers.

● Monolithic Ceramic Sensors: Typically made from a single piece of ceramic material, these sensors have a simpler structure with electrical connections and ASICs (Application-Specific Integrated Circuits) isolated from the medium, offering better compatibility with various media.

3, Application Areas:

● Piezoresistive Ceramic Pressure Sensors: Commonly used in automotive, aerospace, medical equipment, and industrial automation, especially in scenarios requiring dynamic pressure or acceleration measurements.

● Monolithic Ceramic Sensors: Due to their simple structure and good media compatibility, they are often used in applications with severe environmental conditions, such as automotive fuel systems and industrial process control.

4, Performance Features:

● Piezoresistive Ceramic Pressure Sensors: Offer high sensitivity, rapid response, and do not require an external power source, but they may be sensitive to temperature changes.

● Monolithic Ceramic Sensors: May provide better chemical and mechanical stability, as well as a wider operating temperature range.

5, Manufacturing Process:

● Piezoresistive Ceramic Pressure Sensors: The manufacturing process may involve stacking layers of piezoelectric materials, installing electrodes, and polarization treatment.

● Monolithic Ceramic Sensors: Usually made using a single-piece design, formed through a high-temperature sintering process, which may involve metallized plugs and special encapsulation techniques.

The choice between these two types of sensors depends on specific measurement requirements, environmental conditions, and cost considerations. Piezoelectric ceramic sensors are favored for their high sensitivity in dynamic measurements, while monolithic ceramic sensors are widely used in harsh environments due to their structural simplicity and good media compatibility.

Advantages of Piezoelectric Ceramic Pressure Sensors :

● Material Durability: Ceramic materials are known for their hardness and resistance to wear and tear, making them suitable for long-term use in harsh environments.

● Temperature Stability: Piezoelectric Ceramic Pressure Sensors can operate over a wide temperature range, from -40℃ to 125℃, without significant degradation in performance. This is a significant advantage over sensors that are sensitive to temperature changes and may require additional temperature compensation mechanisms.

● Chemical Resistance: Ceramics are generally inert and resistant to most chemicals, which makes them ideal for use in corrosive environments where other sensor types might fail.

● High Sensitivity: Piezoelectric Ceramic Pressure Sensors can detect very small changes in pressure, which is beneficial for applications requiring high sensitivity and precision.

● Long-Term Stability: The stability of Piezoelectric Ceramic Pressure Sensors is typically better than ±0.5%FS/year, which is crucial for applications that require consistent and reliable measurements over time.

● Wide Dynamic Range: These sensors can handle a broad range of pressure inputs, from low to high pressures, without the need for multiple sensor types.

● Fast Response Time: Due to their piezoelectric nature, these sensors can respond quickly to changes in pressure, which is important for dynamic applications.

● No Drift Over Time: Unlike some strain gauge-based sensors, piezoelectric ceramic sensors do not suffer from zero-point drift over time, which can affect the accuracy of measurements.

● Overload Protection: They can withstand pressure spikes up to 2 times their rated full scale without damage, providing a level of robustness that is not always found in other sensor types.

● Compact Size: The small size of these sensors allows for easy integration into tight spaces, which can be a limitation for larger, more cumbersome sensor technologies.

For more information, Please refer to Thick Film Sensors.

Specifications of Piezoelectric Ceramic Pressure Sensors :

Outer Diameter:	18mm * 6.35mm (Height)
Supply Voltage:	30Vdc, (Maximum)
Sensitivity:	3mV/v
Pressure Ranges:	2bar, 5bar, 10bar, 20bar, 40bar, 50bar, 100bar
Full Scale Output:	>2mV/N
Bridge Impedance:	10KΩ ±30%
Zero Point Offset:	<±0.2mV
Operating Temperature:	-40 up to +135°C
Repeatability:	≤±0.2%FS
Safe Overload Pressure:	≥2 times the full scale
Maximum Excitation Voltage:	30Vdc
Insulation Resistance:	≥ 2 KV
Relative Humidity:	0-99%
Temperature Drift (Zero Point & Sensitivity):	≤±0.03%FS/°C
Zero Point Long-term Stability at 20°C:	± 0.25% FS